An uncommon 2,5-diarylcyclopentenone compound, preussidone (1), and a new biphenyl compound, 1',5-dimethoxy-3,5'-dimethyl-2,3'-oxybiphenyl-1,2'-diol (4), together with two known biphenyl compounds, 5-methoxy-3,5'-dimethyl-2,3'-oxybiphenyl-1,1',2'-triol (2) and cyperin (3), were obtained from a Preussia typharum isolate that was procured using a panel of unconventional media formulations. The structures of the new compounds were established by NMR and mass spectrometry, while the absolute configuration of 1 was assigned by quantum chemical ECD and VCD calculations. The antimicrobial and DPPH radical scavenging activities of 1-4 were tested. Compounds 2 and 4 exhibited DPPH radical scavenging activities that were comparable to the positive control ascorbic acid.